The coherent blanking jamming technology is widely applied in the penetration jamming equipment, against which the radars of missile defense systems have few effective countermeasures.Based on existing radar technology, the paper proposes a new method for the countermeasure of coherent blanking jamming on the basis of radar Auto Gain Control (AGC) by studying the inherent defects of the coherent blanking jamming technology based on intermittent sampling.The principle analysis and simulation show that the method is effective in the confrontation of coherent blanking jamming.